Acute sciatica due to a herniated lumbar vertebral disc is one of the most common and disabling conditions affecting the spine. Current therapeutic approaches are generally supportive, consisting of rest combined with narcotic and non-narcotic analgesics;surgery is generally reserved for patients with severe and persistent symptoms. Ample evidence exists showing that much of the nerve-root pain and dysfunction is not due simply to neural compression, but may be primarily due to an inflammatory response caused by the presence of the usually protected nucleus pulposus in the soft-tissue space surrounding the nerve root. Anti-inflammatory therapy, therefore, might prove effective in ameliorating symptoms of a herniated nucleus pulposus (HNP). Epidural steroid injections (ESI's) are frequently given to patients with an acute HNP, though data on the efficacy of this procedure are inconsistent. However, ESI's are expensive, technically demanding, often delayed, and may be ineffective if steroids are not delivered to the target precisely. The use of a short course of oral steroids for patients with an acute HNP is a promising alternative to epidural steroid injections. While many clinicians use oral steroids for HNP, there are virtually no data to support their use. Oral steroids have several potential advantages: they are inexpensive, can be provided by primary care physicians, have no delays in starting therapy and, by virtue of their extended distribution and half-life, may provide a greater and more extensive anti-inflammatory effect than ESI's. Serious adverse events due to a single, short tapering course of oral steroids are uncommon. In this submission, we propose a two-arm parallel randomized clinical trial of a short tapering course of oral prednisone vs. a matched placebo for patients with acute HNP. All participants will have documented a compatible history, physical exam, and lumbar spine MRI to confirm the presence of an HNP. Those participants who show insufficient improvement after the initial treatment (at three weeks) will receive up to two ESI's during follow-up. The primary outcome will be change in the Oswestry Disability Index from randomization to the three-week follow-up visit;secondary endpoints include a visual analogue pain scale and diary, the Dallas Pain Questionnaire, and the SF-36. Participants will then be followed for six months to assess longer-term outcomes. The results of this study will provide crucial information about the benefits and risks of a short course of oral steroids for the treatment of patients with acute sciatica, potentially providing an important new intervention for this common and disabling condition.